Piston



E. M. GATES Sept. 2, 1947.

PISTON Filed May 28, 1945 2 Sheets-Sheet 1 FIG .4.

FIG. I

INVENTOR. EDWARD Molvr GATES A TTORNE Y E. M. GATES.

V Sept. 2, 1947.

PISTON Filed May 28, 1945 2 Sheets-Sheet 2 FIGS.

JNVENTOR. EDWARD MONT G TE;

ATTORNEY Patented Sept. 2, 1947 UNITED STATES PATENT mm;

PISTON Edward Mont Gates, St. Louis, Mo.

Application May 28, 1945, Serial No. 596,266

10 Claims. 1

My invention relates to pistons, and more particularly to pistons forinternal combustion engines, and has for its principal object theprovision of an improved piston of this character in which means areprovided for controlling the clearance between the piston skirt andcylinder walls having different coefiicient of thermal expansion.

A further object is to relieve piston skirt pressure towards thecylinder walls, thus decreasing wear, scoring and fuel consumption, thisresult being accomplished through the varying c0- efilcient of thermalexpansion of the parts involved, and their arrangement and mode ofassembly within the piston.

Another object of the invention is to'provide means, incorporated andmounted within the skirt of a piston'of the kind referred to andsupported from the pillars which are extensions toward the crown of thepin bosses thereof, for controlling under varying temperatures thecircumference of the piston skirt relative to the expansibility of thecylinder walls, and thus maintain the desired amount of clearancebetween the piston kirt and the cylinder walls, the said means includinga pair of equalizing links semicircular in form and of substantiallyless coefficient of thermal expansion than that of the piston itself,and molded or cast or otherwise mounted circumferentially within thepiston and supported in place from the pillars thereof or from separatelugs on the piston skirt below the pillars, the said links beingdisposed at opposite sides of the piston skirt.

With the stated objects in view, together with such other and additionalobjects and advantages as may appear from the following specification,attention is directed to the accompanying drawing as exemplifyingpreferred structural features and embodiments of the invention andwherein:

Figure 1 is a longitudinal or vertical diametri cal section through apistonof the kind referredto, and wherein is incorporated or mounted thesemi-circular equalizing links referred to, the same being supported attheir ends in the pillars of the piston and disposed within grooves onthe opposite sides of the piston skirt, below the head thereof.

Figure 2 is a cross section on the line 2-2 of Figure 1.

Figure 3 is a cross section on the line 3-3 of Figure 1.

Figure 4 is a, longitudinal or vertical diametrical section taken atright angles to the view of Figure 1, on the line 4-4 of Figure l.

, opposite sides of the piston skirt.

Figure 7 is a view similar to that of Figure 1,

showing the equalizing links as mounted within the lower portion of thepiston skirt as well as within the top portion of the skirt as shown inFigures 1 to 5.

Figure 8 is a longitudinal or vertical diametrical section on the line88 of Figure 7.

Figure 9 is a cross section on the line 99 of Figure 7.

This invention is designed for mounting within conventional forms ofinternal combustion engine pistons, such as represented generally at 4and 4a in the drawing in Figures 1 and 7, and which include a pistonhead 5 or 5a, a piston skirt 6 or 6a, connected with the head portion bymeans of oppositely disposed pillars l or la, the head and skirtportions being separated and slightly spaced apart by circumferentialslots or partings 8 or 8a, which slots or partings permit of theexpansion or contraction of the head portion independently of the skirtportion. Addie tionally the skirt portion of the piston is alsolongitudinally slotted as shown at 9 or 9a of Figures 1 and 7, alongdiametrically opposite lines on the skirt portion, intermediately of thesaid pillars and somewhat angularly relative to the longitudinal linesof the skirt, and either terminating short of the lower edge of theskirt as shown in Figure 1, or else extending clear out through thelower edge of the skirt, as shown in Figure '7. The lower ends of thepillars l or la are formed as cylindrical bearings I 0 or Illa, for thecrank-pin (not here shown).

However and due to the fact that the cylinders of internal combustionengines are generally cast of iron or steel having a certain-rate,degree or coeiiicient of thermal expansibility, while the pistons aregenerally cast of some much lighter metal, such as aluminum ormagnesium, having a considerably higher rate, degree or coefficient ofthermal expansibility, the result is thatunder the heat of combustion offuel as generated by the engine in operation, and in spite of the slotsof the piston skirt which allow for and accommodate to a degree for thevariations in the co' efllcients of thermal expansibility of theseelements, the piston and the skirt thereof expand faster and to agreater extent than the walls of the cylinder, and pressing heavilyagainst these walls, cause frictional scoring of both the piston skirtand cylinder walls, causing damage to these elements and wastage of fueldue to the frictional drag of the piston.

In accordance with this invention therefore, additional means areprovided and mounted within the skirt of the piston for equalizing,regulating and adjusting the normally greater thermal expansibility ofthe piston as compared with the lower expansibility of the cylinderwalls. As shown in Figures 1 to the means as provided for this purposecomprise a pair of semi-circular equalizing links H, of substantiallyless coefficient of thermal expansibility than that of the pistonitself, and anchored at their ends within the opposite margins of thepillars I by molding or casting ends in place, the intermediate portionsof the links being additionally supported in grooves l2 formed aroundthe inner walls of the piston skirt and on opposite sides thereofimmediately below the head 5 of the piston, and with their medialportions spanning the parting slots 9, the said links being seated attheir ends within the pillars one above the other in overlappingrelation, with their ends turned inwardly at right angles at oppositedistal margins of the pillars, as clearly indicated at I3 in Figures 2,3 and 5. After the described casting operation as stated, a slightpeening operation on the external sides of the skirt immediately at thepillars, as indicated at M in Figures 1, 2 and 3, will suflice to freethe curved portions of the links as housed within the pillars from anycohesion to the encircling portions of the pillars, thus permitting thefree movement and expansion or contraction of the curved portions of thelinks within the pillars for moving and operating the links in oppositedirections for expanding and contracting the skirt of the piston, thusequalizing and adjusting the minimum and maximum thrust faces of theskirt and by which arrangement the piston skirt as a whole is retardedor expanded contrariwise to its normal tendency under the heat of fuelcombustion and conformably with the normal expansion of the cylinderwalls. While as stated, the inturned ends of the equalizing links areanchored within the pillars by a molding or casting operation in aconventional manner, this anchorage may be made and effected in anyother conventional manner. And it is to be noted that while these linksII are entered into the pillars 1 through one margin thereof, theinturned ends of the links are anchored into the opposite margins of thepillars in an overlapped relation, with the result that due to therelative greater expansibility of the pillars in a transverse directionas compared with the.

lesser expansibility of the links themselves, the lateral expansion ofthe pillars will add to and facilitate and accentuate the equalizingaction of the said links H in operation.

In this way the desired amount or degree of expansion or contraction ofthe elements is regulated and controlled by virtue of the varyingcoefiicients of thermal expansibility of the materials of the pillarsand the equalizing links in co-operation with the spacing of theoverlapped ends of the said links.

The structure as above described relates to the partiall slotted form ofpiston skirt, as shown in Figures 1 to 5. Where the piston skirt isslotted or parted clear down through its lower mar-l gin at each side,as shown at 9a in Figures '7 to 9, the upper equalizing links H andconnections ma be retained, and then an additional pair of semicircularequalizing links Ila may be mounted circumferentially within grooves l2aformed around the inner sides of the skirt 6a, at the bottom of theskirt and across the slots 9a, and anchored at their inturned ends incircumferentially spaced bearings lug 1b, as indicated at 13a, wherebyadditional equalizing meansare provided at the lower end of the pistonfor conforming the expansion thereof within the cylinder walls, inco-operation with the equalizing links at the upper end of the piston.

' While the equalizing links I l and, I la as here shown are round incross section, it is obvious that same might be made in the form of flatsemicircular strips or plates, with mounting apertures of the pillarsand bearing lugs correspondingly formed to receive the ends thereof.

It is thought that the construction and use of theequalizing links asmounted or incorporated within pistons of the kind referred to, will befully understood from the foregoing description, the links at one sideof the skirt controlling the minimum thrust side of the piston, whilethe links at the opposite side control the maximum thrust side thereof,and while I have here shown and described certain preferred forms andstructures of my invention, it is understood that the structuralfeatures as shown may be changed or modified as desired, within thescope of the claims.

What I claim as novel and desire to secure by Letters Patents is:

1. A piston having a skirt, pillar portions having angular recessestherein, and means disposed within the skirt andanchored at its ends inthe recesses, said means having a different coefiicient of thermalexpansion than that of the piston for respectively increasing anddecreasing a portion of the skirt circumference upon cooling and heatingof the piston.

2. In a. piston of the character described, pillar portions having arelatively high coeflicient of thermal expansion and formed withrecesses therein adapted to receive and anchor, accommodate and supportother means having a lesser coeflicient of thermal expansion, the saidlatter means comprising links passed freely withinsaid recesses inover-lapped relation at their ends, and the extremities of the endsbeing inturned into the recesses for anchoring the same therein, thesaid links having a lesser coefficient of thermal expansion than thepillar portions, for wincreasing and decreasing a portion of the, skirtcircumference.

3. A piston including a head portion, a skirt portion, pillars atopposite sides of the skirt portion for connecting the same with thehead portion, and means disposed for free-sliding movement within theskirt and anchored at its ends in the pillars, said means having adifferent coefiicient of expansion than the'pillars for equalizing andconforming the thermal'expansibility of the skirt portion with walls ofa cylinder wherein the piston is mounted,

4. A piston including a. head portion, a skirt portion, pillars atopposite sides of the skirt portion, and equalizing links disposed forfree-sliding movement within the skirt and anchored at its ends in thepillars, said links having a different coefficient of thermal expansionthan the pillars for equalizing and conforming the thermal expansibilityof the skirt portion with the Walls of a cylinder wherein the piston ismounted.

5. A piston for operative disposition within the cylinder of an internalcombustion engine, the said piston including a head portion, alongitudinally slotted skirt portion, pillars at opposite sides of theskirt portion for connecting same with the head portion, and meansdisposed for free-sliding movement within the skirt and anchored at itsends in the pillars, said means having a different coeflicient ofthermal expansion than said pillars for conforming the thermalexpansibilitypf the skirt portion with the walls of the cylinder.

6. In an engine piston of the kind described as mounted within itscylinder, the said piston including a head portion, a skirt portionlongitudinally slotted along opposite sides, and pillars at oppositesides of the skirt portion connected with the head portion,semi-circular equalizing links having a different coeflicient of thermalexpansion than the pillars and skirt and cylinder Walls,circumferentially mounted within the skirt portion and anchored at theirends within the said pillars with their ends overlapped within thepillars, as means for conforming the thermal expansibility of the skirtportion with the cylinder walls.

7. A pistoninclucling a head portion, 'a skirt portion, pillars atopposite sides of the skirt portion, semi-circular linkscircumferentially connecting the pillars inside the skirt portion, saidlinks being freely supported within grooves formed around the innersides of the skirt portion and being anchored at their ends within thepillars in overlapped relation, at opposite margins of the pillars,except for their anchored ends the links being free to expand orcontract within said pillars, said links being of lesser coeflicient ofthermal expansibility than the pillars, whereby due to the greatertransverse expansibility of the pillars the lateral expansion of thepillars under the heat of combustion, the said links will equalize theexpansion of the skirt portion conform-.

ably with the expansion of the cylinder walls of the cylinder withinwhich the piston is mounted. 8. In a piston of the character describedand including head and skirt portions and pillars at opposite sides ofthe skirt portion, semi-circular equalizing links circumferentiallyconnecting the pillars inside the skirt portion, the ends of the linksbeing passed freely into the pillars from opposite sides thereof inoverlapped relation and anchored at-their inturned extremities in theopposite margins of the pillars, said links being of differentcoefiicient of thermal expansibility than the pillars, for increasingand decreasing the piston skirt under the heat of combustion.

9. In a piston of the character described and including head and skirtportions, semicircular equalizing links for circumferentially mountingwithin the skirt of the piston, said links being of differentcoefficient of thermal expansion than the skirt portion and beinganchored at their ends to the skirt portion with said ends arranged inoverlapped relation, for controlling the expansibility of the skirtportion under the heat of combustion.

10. In a piston of the character described and including head and skirtportions, a pair of semicircular equalizing links for circumferentiallymounting within the skirt of the piston with the ends of the linkspositioned in overlapped relation and anchored at their inturnedextremities to the skirt portion, said links being of differentcoefi'lcien't of thermal expansion than the skirt of the piston forcontrolling the expansibility of the latter under the heat ofcombustion.

EDWARD MONT GATES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

